1. Field of the Invention
The present invention relates to a production process for insert decorated moldings for forming various decorated moldings for vehicles, houses, furnitures and the like.
2. Related Art
Various trials have so far been made in order to meet the desire that two or more kinds of continuous pictures are provided in a molding step of plastic moldings. Available is, for example, a method in which a plastic molding is provided with two or more kinds of continuous pictures by an in-mold method in producing decorated moldings. That is, it is a method in which a base film is provided with two or more kinds of continuous pictures and in which the pictures are transferred onto a plastic molding in a metal die.
However, though the above method is effective when drawing is small, registration of pictures is difficult when it is applied to deeply drawn moldings, and the moldings are provided with a low design property.
Further, a method in which two or more kinds of continuous pictures are provided by a hydraulic transfer method is available. However, a mask has to be coated, and the work is complicated. In addition thereto, a solvent which exerts a high load on the environment has to be used, and therefore it is not necessarily a preferred method.
On the other hand, a method in which two or more kinds of pictures are provided is proposed as well in an insert molding method. It is, for example, a method in which in a case where decorations such as woodgrain patterns are provided on one face of a tabular resin molding and where a metal lustrous layer is formed on the other face, a decorative sheet on which woodgrain patterns are formed and a decorative sheet on which metal lustrous patterns are formed are disposed in a metal die and in which a molten resin is injected between two decorative sheets to provide the decorative films integrally on both faces thereof at the same time as forming a resin molding (refer to a patent document 1).
However, though the above method is applicable in a case where two kinds of decorative sheets are provided apart, it is difficult to apply it when two kinds of pictures are continuously provided. That is, two sheets of the decorative sheets are shrunk in injection molding, and therefore it is difficult to allow the end parts thereof to stay in a state in which they are completely brought into contact with each other; as shown in FIG. 1, a gap S is formed at a boundary part between two kinds of a decorative sheet 10a and a decorative sheet 10b, and a molten resin flows thereinto. This allows the color of the resin to be observed at the boundary part between two kinds of the continuous pictures when the molding is formed, and the design property is damaged.
On the other hand, if two kinds of the decorative sheets 10a and 10b are superposed as shown in FIG. 2 so that a gap is not produced at a boundary part between two kinds of the pictures, the resin is not penetrated into a part L in which the decorative sheets are overlapped, and therefore the decorative sheets are not adhered to the resin molding at the part. Thus, the decorative sheets stay in the state that they are partially peeled off, and they are reduced in a design property.    Patent Document 1: Japanese Patent Application Laid-Open No. 254938/2000